BISMILLA HIR RAHMAANIR RAHEEM
All the previous Ambiyaa (A.S.) informed their respective Ummats about the signs of Qiyamah, but Our Beloved Nabi Sayyidena Muhammad (Sallallahu Alayhi Wasallam) informed his Ummat about these signs in much greater detail. The reason being that there is no Nabi to come after him and his Ummat is closest to the advent of Qiyamah, hence they need to make greater preparation for it by reforming their spiritual selves, controlling their passions and diligently carrying out the orders of Allah Ta'ala.
According to a hadeeth appearing in Sahih Muslim, Sayyidena Abi Zaid (R.A.) says, " Rasulullah (Sallallahu Alayhi Wasallam) once led the Fajr Salaat after which he ascended the pulpit and addressed us till Zuhr Salaat. He alighted from the pulpit, performed Zuhr Salaat and ascended the pulpit. He then addressed us till Asr and descended from the pulpit. He performed Salaat and ascended the Mimbar. He then addressed us till sunset (In these sermons) He informed us about those incidents which had occured as well as those which are yet to occur. Those with stronger memories amongst us remembered most of them."
The above hadeeth as well as other Ahadeeth indicate the importance attached to the imparting of information pertaining to Qiyamah. It is further reported that the Noble Companions used to teach the Ahadeeth to their children instructing them to convey it to others.
It will be noticed that while some Ahadeeth mention very briefly certain signs of Qiyamah, other ahadeeth again mention certain signs in greater detail eg. the coming of Sayyidena Eesa (A.S.), Imaam Mahdi (A.S.) and the advent of Dajjal. This is so because of the fact that these signs are a greater test for one's Imaan.
Another important point is that despite the large collection of Ahadeeth which exists in regard to the signs of Qiyamah there is no specific order mentioned in as far as the occurance of many of the events is concerned. The exact period between each sign is also generally unknown.
Further, certain signs have been mentioned very briefly, thus making it difficult to specify exactly as to whether or not a certain event which has occred or is occuring is the same one which the Ahadeeth has mentioned. The reason for all these above factors is to disable anyone from reckoning the exact time of Qiyamah which Allah has said will occur suddenly... "It will come upon you suddenly." (Quran)
Mohammed Ali Ibn Moulana Zubair Ali